I have made a 1 shot kill on a small fork mule deer at a measured 604 yards with my 25-06 and a 115g BT. The buck was hit in the shoulders and went about 20 yards or so then died. It had roughly right at 1000 lbs of energy at the deer. Thats what I go by. Obviously the .257 Weatherby Magnum is gonna out do the 25-06 by at least 200fps. It is at least a 700 yard killer in terms of numbers on a computer screen, but if thats what everyone insists on going by, then by all means the 257 WM will kill farther then the 25-06. Funny how some say its no more then a 300 or 400 yarder, but I'm only shooting at the largest a big 4x4. Usually my bucks dress out at 120 lbs.